1. Field of the Invention
The present invention relates to a release film, and more particularly to a release film for supporting an ultrathin ceramic green sheet having a thickness of 0.5 to 1.0 μm and a process for producing the same.
2. Description of Related Art
A generally known ceramic green sheet 10, as shown in FIG. 1, is a ceramic lamination material widely used in association with multilayer technology, which is formed from ceramic slurry and covered over a release film 20 via a method of tape casting or doctor blade method.
Recently, thanks to advancements in ceramic film lamination techniques, the ceramic green sheet 10 has been made thinner and thinner, from 1.0-5.0 μm to merely 0.5-1.0 μm in thickness. And, as defined in field of ceramic green sheet, a ceramic green sheet with a thickness of 0.5 to 1.0 μm is hereinafter referred to as an ultrathin ceramic green sheet 10a. 
Particularly, the ultrathin ceramic green sheet 10a can be used to make multilayer ceramic capacitors (MLCC) with a capacitance greater than 1 μF, which is a breakthrough in the art considering that the capacitance of a traditional MLCC ranges only from 0.1 to 1.0 μF.
However, the release film 20 of FIG. 1 conventionally used to support a ceramic green sheet 10 having a thickness greater than 1.0 μm is unsuitable for supporting the ultrathin ceramic green sheet 10a. This is because the conventional release film 20, as disclosed in US2006/0222814A1, tends to attach or adhere so firmly to the ultrathin ceramic green sheet 10a, so that a relatively great electrostatic force is generated between them when the ultrathin ceramic green sheet 10a is peeled off the release film 20, and the ultrathin ceramic green sheet 10a may break due to the electrostatic force if not peeled off properly.
In order for the release film 20 to better support and release the ultrathin ceramic green sheet 10a having a thickness of 0.5 to 1.0 μm, the release film 20 must provide a releasing surface with a better flatness and provide a film thickness with a better uniformity as well as provide a releasing force more stable, when compared with any counterparts in the prior art.